The Baltimore Orioles selected Heim in the fourth round, with the 129th overall selection, of the 2013 MLB draft. He signed with Baltimore, receiving a $389,700 signing bonus, rather than enroll at Michigan State.[7] He made his professional debut that season the GCL Orioles and spent all of 2013 there, slashing .185/.275/.247 in 27 games. In 2014, he played for the GCL Orioles and the Aberdeen IronBirds where he batted .196 with one home run and seven RBIs in 46 games, and in 2015, he played for the Delmarva Shorebirds where he compiled a .248 batting average with one home runs and 16 RBIs in 43 games. He began 2016 with the Frederick Keys.

On August 1, 2016, the Orioles traded Heim to the Tampa Bay Rays for Steve Pearce.[8] Tampa Bay assigned him to the Charlotte Stone Crabs and he finished the season there. In 102 total games between Frederick and Charlotte, he collected a .217 batting average with eight home runs and 33 RBIs. He spent 2017 with both Charlotte and the Bowling Green Hot Rods, slashing .260/.317/.402 with nine home runs, 61 RBIs, and a .718 OPS in 93 games.[9]

Jefferies attended Buhach Colony High School in Atwater, California where he both pitched and played shortstop. As a junior in high school, Jefferies was named Central California Conference MVP after going 8-0 with a 1.26 earned run average (ERA) and putting up a .366/.480/.505 slash line. Daulton's senior season was equally as impressive as he went 10-2 with a 0.92 ERA and a school record 142 strikeouts, again taking home the Central California Conference MVP.[11] Jefferies had initially verbally committed to play baseball for Stanford University during the summer of his junior year of high school, but the offer fell through and Jefferies was forced to find another school, eventually deciding on the University of California, Berkeley.[12]

As a freshman for the California Golden Bears in 2014, Jefferies started 15 games, finishing the year 2-8 with a 3.45 ERA and 58 strikeouts in a team-high ​922⁄3 innings. Jefferies' sophomore season saw both his record and earned run average improve, as he appeared in 14 games, starting 13, and went 6-5 with a 2.92 ERA, enough to warrant a First Team All-Pac-12 selection.[13] The summer after his sophomore season, Jefferies was a member of the USA Baseball Collegiate National Team.[14]

Jefferies was drafted by the Oakland Athletics with the 37th overall pick of the 2016 MLB Draft.[15] He spent his first professional season with the AZL Athletics where he posted a 2.38 ERA with 17 strikeouts in 11.1 innings pitched.[16] He pitched in only two games in 2017 before undergoing Tommy John surgery, thus ending his season.[17]

Jefferies has a four pitch repertoire. His fastball has a bit of sink and sits in the low-to-mid 90's, but can top out around 96 mph. His primary off-speed pitch is his changeup which he throws in the mid-80's with good sink and fade. He also has a decent slider and a good three-quarters curveball.[18]

White was drafted by the Oakland Athletics in the second round of the 2015 MLB Draft.[53] He signed with the Athletics and made his professional debut with the Vermont Lake Monsters, and he was later promoted to the Beloit Snappers; he posted a combined .253 batting average with three home runs and 28 RBIs in 64 games between both clubs. He spent 2016 with the Stockton Ports where he batted .247 with six home runs and 50 RBIs in 124 games. In 2017, he returned to Stockton, and posted a .261 average with 17 home runs and 73 RBIs in 115 games.[54] He began 2018 with the Midland RockHounds.